Roy,
Last Friday, we had a similar experience, when one job leads to another, to yet another.
We were in Shirenewton cleaning the Tredegar Arms and some posh lady walking her dog asks me for a quote.
The house was just round the corner, a large place and we quoted and got it for £30 (though I wish I quoted higher; her gardener even seemed posh and later into the clean an 'interior designer' called).
But this lady then said to call into the Spar shop, since she originally asked if they knew any window cleaners and they said they didn't, but wanted one.
So we did; that was another £15.00 every two weeks (house as well as shop), but then they referred us to one of their staff who wanted a window cleaner.
So we ended up with a lot of work we didn't expect.
With it being a Friday, we were frightened to make eye-contact with other people, just in case they 'nabbed' us too.
We planned an early finish.